1. Field of Invention
The present invention relates to a moving granular bed.
2. Related Art
The industrial contaminants such as particulates, acid gas (e.g. HCL, SO2, NOx), and organics commonly cause the air pollution, so that these contaminants must be processed before they are discharged. If not, the contaminants can generate a huge impact to our environment. In order to remove the contaminants, the granular bed filter was disclosed many years ago for simultaneously remove dust particulates contaminant and SO2 contaminant at high temperature (>400° C.). In general, the granular bed is divided into four kinds of reactors: (1) a fixed bed, (2) an intermittent moving bed, (3) a continuous moving bed, and (4) a moving granular bed. The moving granular bed is also called a fluidized bed, which is widely applied to various kinds of industries. Since the moving granular bed has the physical and chemical applications and can remove different kinds of contaminants, it has an excellent potential for cleaning the complex smokestacks gas generated by the incinerating process.
FIG. 1 is a schematic diagram showing a conventional moving granular bed 1, which includes a filter granule channel 11, an inlet unit of gas 12, and an outlet unit of gas 13. The filter granules 111 is filled into the filter granule channel 11 through a inlet of filter granules 112 in a slow moving way, and is left the filter granule channel 11 through an outlet of filter granules 113. The dirty gas enters through the inlet unit 12 to arrive one side of the filter granule channel 11. Accordingly, the dust particulates and contaminants contained in the dirty gas can be collected by the filter granules 111 and then took away by the filter granules 111, which moves from the top to the bottom slowly and finally out of the filter granule channel 11 through the outlet of filter granules 113. At the meantime, the filtered clean gas can flow to the outlet unit 13 disposed at the other side of the filter granule channel 11, and then be exhausted through the outlet unit 13.
In the moving granular bed 1, however, when the dirty gas enters through the pipes of the inlet unit 12, its velocity distribution usually has a single peak, which means that the gas velocity at the center of the pipe of the inlet unit 12 is higher than that near the wall of pipe due to the wall effect. Because the gas velocity can not be efficiently distributed and controlled, the collection efficiency of the filter granules 111 for filtering the dust particulates can not be optimized. Moreover, some filter granules 111 may pass through the entire filter granule channel 11 without collection anything, which sufficiently decreases the usage of the filter granules.
Therefore, it is an important subject of the invention to provide a moving granular bed that can input the dirty gas into the filter granule channel with uniform velocity distribution so as to improve the usage of the filter granules.